This invention relates to a truss header for use in adjustable shoring structures. More particularly, the invention relates to a truss header employed in unitary concrete form assemblies known as flying slabs which is of an adjustable length and provided with an unweighted camber whereby the truss header will tend to straighten or flatten out horizontally in response to applied loading conditions.
Adjustable shoring systems made of reusable form components are conveniently and efficiently used in the construction of concrete floors in office buildings, high-rise structures and the like. The form components can be easily and quickly assembled and thereafter removed for transport to another pour site. Because efficiency can be increased by pouring concrete floors across large spans, shoring systems for the pouring of floors across spans of up to thirty feet are manufactured in modular form. These assemblies are preferably of the flying slab type, such as that disclosed in U.S. Pat. Nos. 3,899,152 and 4,106,256, wherein combinations of shoring apparatus and deck forms are designed to be placed in side-by-side and end-to-end relation to provide a continuous deck form which serves as a base for the poured concrete.
The thickness of a poured concrete floor may be up to twelve inches for a span of twenty-three feet. The weight or load of such a quantity of concrete requires a heavy conventional truss to maintain the floor level within the usual tolerances. As the thickness of the floor to be poured and the span length increases, so does the weight of a truss constructed to provide adequate support. Additionally, the heavier supporting apparatus requires a larger and more expensive crane to "fly" the modular assemblies between pour sites.
The truss header of the present invention offers an improved supporting assembly for pouring long span concrete floors. The truss header is designed with a camber which tends to straighten out in response to the applied load of the poured concrete whereby a lighter-weight material, such as aluminum, can be used in its construction to efficiently carry a predetermined load.